Burman B52 -

56G80S · Post by **56G80S** » Mon Aug 04, 2008 9:37 pm

Thought it best to start a new thread as I am now not concerned about the CP clutch fitted to a B52 box, but a related, separate, matter.

I discovered that the final drive sprocket was loose. So I checked in the F W Neil book covering 1956 and read that "...this nut is usually very tight and difficult to undo..." I released the lock washer, used a very close fitting box spanner (that Dad had left me in a toolbox with lots of them) and wound the inordinately large nut up very tight, refitted lock washer. Don't worry, there's lots of tabs left.

But now I seem to have preloaded the bearings in the gearbox, as I can only turn the mainshaft with difficulty. I have to put a piece of cloth on it to turn it with my fingers. Of course, the kickstarter rolls it over easily - but it would wouldn't it?

Before tightening up there was a little endfloat on the mainshaft, but very little. It was turning freely. Do I assume I'm too heavy handed, wind off the big nut until the mainshaft turns more easily and then turn the lock washer up?

I rebuilt the box with new bushes, bearings and necessary replacements for worn parts some 5.000 miles ago and it's been fine so long as I don't rush the changes.

Wish I'd left it alone. Can I wiggle the box out if I loosen off the drive side engine plate? And slip the "jump out of 1st gear probably needs new detent" AMC box back in with it's nice relatively new and "only problem was centre nut undoing" clutch?

I just want to be riding it again!

Johnny B

itma · Post by **itma** » Mon Aug 04, 2008 10:24 pm

I hate gearbox problems when its not in front of me.
I would suggest pehaps a spacer is misplaced some where.
The sprocket nut can be done up bloody tight, I use a chain looped round and held in a vice, plus a big ssocket.
I have never had any problems resulting fron that action so I would double check things on the mainshaft, which means a strip.Not a lot of help, but I am relying on memory only.
you should be able to wiggle the box out by loosening all the engine plate nuts, usually it comes out the timing side and probably you will have to remove the oil pipes.
What you really need here is Alan's wisdom,lets hope he gets well soon.

56G80S · Post by **56G80S** » Mon Aug 04, 2008 11:25 pm

Thanks a lot for the suggestion. It may be a spacer issue as I slapped the whole thing back together very quickly from memory after a long time in bits.

I was very self satisfied that I could remember how after 12 years and had all the parts - perhaps I was wrong!

Johnny B

John_LAPSED · Post by **John_LAPSED** » Tue Aug 05, 2008 9:50 am

From your posting am I right in thinking that the box is stiff on the main shaft but not locked solid.

Does the box remain stiff when in neutral?

When you replaced the bearings in the box did you replace the bushes in the sleeve gear?

My guess is that the main shaft is slightly bent and/or there is not enough clearance in the two sleeve gear bushes, and tightening up the sprocket nut has stopped the sleeve gear from slightly swirling with the main shaft as it is turned.

I hope this has gives you some ideas.

John

56G80S · Post by **56G80S** » Tue Aug 05, 2008 8:24 pm

John

Thanks for the suggestion. I'm going to remove the sprocket, explore the possible spacer cause. But if that's not it, I'll take the B52 out, put the "wrong for year" AMC box and clutch back in and then take another look at the B52. Then I'll have got a rideable 'cycle for the remainder of the summer. Even if I have to pull away in second (no, really I'll take a look at the obvious jumping out of 1st causes but only easily accessible ones).

As I wrote before, all the bushes and bearings and some other parts were replaced and the box gave no trouble until I tightened up the sprocket nut on the sleeve gear.

It can keep me busy on the dark nights! And I'll refurb. the other spare AMC while I'm at it just in case.

Johnny B

itma · Post by **itma** » Tue Aug 05, 2008 10:25 pm

thought has also occured to me that maybe the sleeve gear bushes are tight onthe shaft, perhaps the sprocket has pulled up on them ?
Always start at the last thing you did.

56G80S · Post by **56G80S** » Thu Oct 02, 2008 11:04 pm

Just to round this off, because people had bothered to respond and it seems rude not to give feedback on what happened.

In the end I squirted extra oil in and worked the mainshaft round a lot by hand and followed up with kicking it over a lot before refitting the clutch. When it got easier I fitted the clutch and went for a short run and checked if it had all got hot / tight. No.

So I've now done 4 or 5 of my 72 mile round trips to work and all's fine. In other words - don't be such a fusspot!

Thanks all.

Johnny B

wilko · Post by **wilko** » Fri Oct 03, 2008 2:22 am

My B52 did the same thing when i swapped my mainshaft. It didn't have any end play, so i just cut out a thicker inner gasket which fixed the problem. Somebody in the past probably had the same problem and just left the nut loose to give a bit of freeplay! Dugless.